// TrafficWatcher - a network speed monitor

// Copyright (C) 2008-2009 - Stefan Kueng

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software Foundation,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//

#include "stdafx.h"
#include "Filter.h"

CFilter::CFilter(void)
{
    for (int i=0; i<FILTER_MEAN_DEPTH; ++i)
        diffs[i] = 0;
    dwTotalOld = 0;
    dwPrevTicks = 0;
}

CFilter::~CFilter(void)
{
}

void CFilter::Clear()
{
    for (int i=0; i<FILTER_MEAN_DEPTH; ++i)
        diffs[i] = 0;
    dwTotalOld = 0;
    dwPrevTicks = 0;
}

DWORD64 CFilter::Filter(DWORD ticks, DWORD64 value)
{
    DWORD diffTicks = ticks - dwPrevTicks;
    dwPrevTicks = ticks;

    DWORD64 diffValue = value - dwTotalOld;
    dwTotalOld = value;

    DWORD64 meanDiff = diffValue;
    for (int i=0; i<FILTER_MEAN_DEPTH; ++i)
        meanDiff += diffs[i];
    meanDiff /= (FILTER_MEAN_DEPTH+1);

    for (int i=FILTER_MEAN_DEPTH-1; i>0; --i)
        diffs[i] = diffs[i-1];
    diffs[0] = diffValue;

    if (diffTicks)
        return meanDiff * 1000 / diffTicks;
    return 0;
}

void CFilter::Init(DWORD ticks, DWORD64 value)
{
    Clear();
    dwPrevTicks = ticks;
    dwTotalOld = value;
}
